Adam Berkowitz, who in 10 years at the William Morris Agency has represented a host of television writer-producers, departed the percentery Thursday for a position as an agent in the TV packaging department at Creative Artists Agency.

Competitors viewed the departure as a significant hire for CAA as well as a hit for WMA. It was unclear which clients would follow Berkowitz to his new employer. He informed WMA agents of his decision to leave Thursday and had taken an office at CAA by later in the day.

For agencies, writer-producers are key elements in obtaining lucrative packages for primetime shows, fees that have long been considered the bread and butter of the agency business.

Decade of repping

In 10 years at Morris, Berkowitz has repped writer-producers such as John Bowman (who has an overall deal at Warner Bros.), Bill Diamond (executive producer of “Murphy Brown”), Alan Kirschenbaum (who has an overall deal at TriStar), Jane Milmore and Billy Van Zandt (who have an overall deal at Warner Bros.), Theresa Rebeck (“NYPD Blue” producer), Phil Rosenthal (executive producer of “Everyone Loves Raymond”), Peter Tolan (who has an overall deal at Disney), and Jorge Zamacona (co-executive producer of “Millennium”). He also has handled the career of Lorenzo Carcaterra, author of “Sleepers.”

Berkowitz, 35, began working at WMA in 1979 as a summer intern and, while working for the agency, completed law school and became a member of the New York Bar Assn. In 1995, he moved from the New York Morris offices to Los Angeles, joining its West Coast television offices as a packaging agent.

“I’m truly excited to have the opportunity to be part of CAA’s television department,” he said in a statement. “I’ve learned so much in my tenure at William Morris and will be leaving behind many close friends.”

Latest TV shakeup

Berkowitz’s departure is the latest shakeup in the TV departments of both agencies in the past 18 months. Morris’ TV head Bob Crestani left for the Comcast venture C3. CAA lost Marty Adelstein and Michael Rosenfeld as well as co-founder Bill Haber.

CAA, however, did top the other agencies in packaging in last year’s fall schedules. Eyes now are on the TV devel-opment season.

Berkowitz “is a dynamic agent with a proven track record,” Lee Gabler, co-chairman of CAA, said in a statement. “His experience, diligence and taste will complement our extraordinary team of agents. Adam has a keen eye for emerging talent and has proved to be a skilled career adviser.”